Thermostatic radiator valve



Sem. 6, w49. N. WALKER 2,480,986

THERMOSTATIC RADIATOR VALVE Filed May 29. 1947 f .l/M

Womens Patented Sept. 6, 1949 OFFICE 2,480,986 'rnERMosTA'rrc Vimnm'ron vALvE Nelson Walker, Flint, Mich., assigner to General Motors Corporation, Detroit, Mich., a corporation of Delaware Application May 29, 1947, Serial No. 751,287 3 Claims. (Cl. 236-92) To increase efficiency of an engine cooling system and enable reduction in the liquid content volume and the size of the parts and thereby effeet savings in weight and cost, it has become general practice to seal the system for operation under internal pressure with suitable safety valving to eliminate strain from large pressure diferential. Further to minimize stress under certain engine operating conditions and obtain the desirable advantages of an open system including quick warm-up it is proposed to provide for sealing the system under safety valve control only after a given operating temperature has been reached.

More particularly an object of the present invention is to provide an improved temperature control device which occupies a minimum of space, is reliable and carefree over long periods of hard usage and is inexpensive to manufacture. Contributing largely to the desired result is the employment of a comparatively long and narrow birnetal strip which is' brought into a compact and convenient overall size and shape by winding the strip helically and also helically winding the coil. Whether two helical winds are done concurrently in one operation or separately in succeeding operations there will be produced a double helix bimetal coil of relatively large surface area for a rapid response and an extensive range of contraction-expansion with temperature change.

The operation and novel features will be better -understood upon referenceto the accompanying drawing wherein Figure l is a side elevation showing an engine cooling system to which the invention may be applied; Figure 2 is a vertical sectional view showing the control valve assembly conveniently embodied in the removable closure cap for the vented ller spout and Figure 3 is a perspective view of a bimetal strip wound to double helix form.

In the drawing the lower header l at the bottom of the radiator core 2 is joined by a hose connection 3 to the engine driven pump 4 at the front of the jacketed engine block 5. The upper header tank 6 is joined by a rubber hose connection l with the outlet of the engine cooling jacket and is provided with a ller spout 8 from which leads the usual overflow and vent pipe 9 extending downwardly beside the radiator. The removable closure cap l may be secured to the spout 8 by the well known bayonet type connection and its carries a central rivet Il by which is secured a springwasher I2 to peripherally '2 engage and seal the upper end of the spout t when the cap I0 is turned down tight.

Also secured by the rivet M is a valve unit for closing the system from the interior of the vented spout 8 and which unit includes an outer cage element or cup-shaped stamping I3 swivelly mounted at its upper end by a shouldered portion of the rivet il. the wall of the cage provide communication from its interior into the spout and the bottom edge of the cup is flanged outwardly for mounting therein a centrally apertured plate or washer it, which is crimped behind the outturned ilange at a number of places, as shown at l5. At its rim the plate Ill is formed with a circular bead to seat against a sealing gasket i6 positioned at the bottom of the spout. Tight seating at this point is effected when the radiator cap i0 is drawn down tightly and this seal is broken upon initial turning back of the cap so that internal system pressure can be relieved before the cap is completely removed from the spout. Sleeved onto a dependent skirt at the central opening in the plate i4 and preferably soldered thereto is an additional cage element or cup Il to complete the protective enclosure of the control valving. It has one or more free openings through the wall thereof.

A raised circular rib at the central opening in the plate it aiTords a seat for a gasket ring IIB forming a part of an outwardly opening hollow valve body. A backing for the gasket I8 is afforded by an outturned ange on a centrally domed member I9 and is retained in place by a shoulder on a tubular member 20, whose upper end telescopes Within and is press fitted to the cylindrical wall portion of the domed member il) to form a unit therewith. A coil spring 2| has one end pocketed or located within a shouldered portion of the end Wall of the cup i3 and its coils at the opposite end surround the domedmember I9 and seat on' the lower outturned flange to yieldably urge the gasket I3 against its seat on the washer ld and resist outward movement of the valve unit under internal pressure. For the ordinary automobile engine cooling system a spring which Will be deected at about four pounds internal system pressure has been found to be satisfactory.

The upper Wall of the domed member i9 is apertured and the marginal rim is pressed downwardly and outwardly to retain in position a sealing gasket 22 forming a seat for a peripheral portion of a lightweight valve disk 23 which is free or unattached to any other part but con- One or more openings in 3 ned within the space existing between the gasket 22 and the upper end or tip of a slidably reciprocable guide pin 24, whose lower end slidably projects through and is guided within an opening of a supporting member 25 axially adjustably mounted in the lower end of the tubular member 20, as by means of interengaged screw threads. Fixedly carried near the upper end of the guide rod 24 is an enlarged abutment head or seat in the form of a, flanged c ollar 26. When the pin 24 and its collar 26 are separately formed, as shown, they may be iixedly secured together in any suitable manner as by a proper located depression in the rod 24 and into which is pressed or peened a portion of the metal of the collar in the manner illustrated at 21. The relative location of the parts should be such that the upper tip portion of the pin 24 projects beyond the top of the abutment head for approximately 51E of an inch to afford a central button of relatively 'small diameter and on which the valve disk 23 may have a fulcruming engagement so that if the disk 25 is pushed or forced upwardly by the pin it centers itself when seating against the gasket 22. The fulcruming abutment also insures that the runderside of the disk 25 is spaced above the top of the head 26 with its major surface area exposed to the action of pressure internally of the system. Thus a surge of internal pressure or a sudden inertia flow of water in the upper radiator tank, caused by a quick stop of the vehicle, may tend to raise and close the valve even though the guide pin 24 is in the retracted cold position shown.

For projecting the guide pin 24 and forcibly seating the valve disk 23 when system temperature is such as to call for greater heat dissipation through pressure operation there is interposed between the abutment head 25 and the lower seatingwall 25 the double helix coil 28 formed of a suitable length of bimetal strip Wound helicallyinto a coil with the coil wound helically as shown in the drawing. At low temperature the double helix coil 28 will be contracted and with the parts as shown in Figure 2 the system is open to the vent tube since the valve disk 23 is away from its seat or in by-."

passing relation to the sealing rings I6 and .IB. Expansion or elongation of the thermostatic .coil 28 will lift the disk valve 23 towards its seat and eventually seal the system and thereafter the system will operate at whatever internal pres# sure is generated upon further thermal expansion of the liquid contents up to the limit aiforded by the spring force acting on the safety blowoff valve to vent the system by lifting the gasket I8 from its seat. Determination of the closing temperature under the influence of the coil 28 will be dependent upon the particular installation and operating problems involved and as an example of a suitable closing temperature in the case of conventional engines for passenger pleasure automobiles there has been specified a temperature of approximately 140 F. When `engine temperature again drops off the coil will contract and move the pin 24 away from the valve seat -22 in the apertured end wall of the valve body and unless internal system pressure exceeds atmospheric pressure the valve disk 23 will drop away from the seat. Also the coil 28 will have a certain degree of elasticity so that even though it may be in an expanded condition it will yield for unseating the valve under a pressure differential in -whichthe internal pressure is somewhat below atmospheric pressure. In

the cooling oif period and after contraction of the coil 28 has progressed to enable the disk 23 to drop there may be conditions, such as afterboiling, in which momentary internal pressures are built up and which, because of the underside exposure of the free valve 23, will raise the valve and seal the system under control solely of the blowofl' spring 2l. Primarily the structure involved provides a compact and foolproof 10 unit whereby the system is safely sealed for high temperature operation but is desirably vented for operation at low temperature.

I claim:

1. In a pressure vent valve for heat exchange systems, a chambered body providing a passage therethrough arranged to be open below a given system temperature, an axially elastic helical coil of bimetallic strip located in said passage, a reciprocable guide stem carrying a seat for the operative end of the coil to be shifted upwardly uron coil elongation toward a valve seat in the passage, a central button like extension beyond said seat and a downwardly opening disk valve confined within the chamber between the valve seat and the button but otherwise free and unattached so as to be blown upwardly against its seat by internal pressure and to be blown downwardly by external pressure away from its seat within its confinement limit, said disk valve and buttonbeing arranged for rocking abutment and the axial confinement of the disk valve being variable with system temperature variations within predetermined limits and the variation below the upper valve seat limit enabling unrestricted unseating of the valve at external pressure higher than system internal pressure.

. 2. In a pressure vent valve of the character described, a pressure responsive blowoff valve, a valve seat surrounding a vent opening, tempera- 4o ture responsive control means including a downwardly opening disk valve for cooperation with said seat, said valve being arranged to drop away from said seat and to be responsive to pressure differential on opposite sides of the valve and being freev of direct connection with any operating part, a helical coil of bimetal strip arranged to seat said disk valve upon elongation and thereby increase the pressure differential at which the valve will respond, and a guide therefor comprising a slidablymounted pin having fixed thereon a bearing seat for the coil and a rocker abutment projected beyond said .seat to contact without fixed connection with a central portion of the disk valve and enable a self-centering action of the disk valve in relation to its seat'.

3. Control valvingV of the character described, including a chambered body, one end wall of which is apertured and surrounded by a valve seat, a helical bimetal strip seated at one end on the other wall and thermally expansible and contractible toward and away froml the valve seat, a guide and seat abutment for the other end of the helical strip having a locating pin projected at its upper end tip beyond the said abutment and a downwardly opening free valve disk confined but unat- 1iuid pressure differential on opposite sides of the disk and movable toward and from its seat in A response to expansion-contraction of the helical strip in cooperation with fluid pressure differential and being of thin lightweight material peripherally engageable with the valve seat and centraliy engageabie with the pin tip, which latter maintains the underside of the valve disk spaced from said abutment with substantially its entire area exposed to internal system pressure.

NELSON WALKER. 5

REFERENCES CITED The following references are of record in the file of this patent:

Number UNITED STATES PATENTS Name Date Lijeski Jan. 26, 1926 Muy t Feb. 12, 1935 Kistner Feb. 21, 1939 Eshbaugh Feb. 11, 1947 Chace Jan. 13, 1948 

